Which of the following sentences illustrate(s) the proper use of commas?

Which of the following sentences illustrate(s) the proper use of commas?

A. Randy wanted to end the meeting, but Amy wanted to prolong it.
B. After pouring herself a glass of water in silence, Nicky answered my question.
C. The committee, which had failed to come to a consensus decided to meet again on Tuesday.
D. Mr. Bridges is never home on the weekends, he always goes to his home in the country.
E. a and b
F. All of the above

Answer - D